No. Your battery degrades each time there's a cycle of charge->use. If you're lucky, you can do that a few thousand times before you lose much of your battery's capacity. If you leave it plugged in, you aren't losing cycles, so you should do that.
A cycle from say 70% to 80% doesn't wear it out much at all.
The problem with leaving it at 100% is that just sitting at full charge wears it out, it's better to just keep it within 40%-80% than to leave it fully charged.
If the indicators are correct, HP's chargers keep the batteries at ~95% (varies between 95-100% all the time). So they're not keeping them fully charged or overcharged, but instead leave some breathing room.
A 40% depth discharge is going to put way more wear than leaving it at 100%. Unless you want to plug and unplug constantly most users are probably best leaving it plugged while working.
If you really want to, you can do a little bit of good by letting it drop to 40=80% during periods of non-use.
Emphasis on "well designed". The 500€ laptops I've experienced in the past weren't and you could murder the battery like this in couple months, no matter the brand (HP, Dell).
AFAIK only macbooks have been designed to bypass battery ( once the charge is 100% ) and directly run on connected power. For other notebooks its best to unplug charger at 100% and connect charger at around 10% to get a longer lifetime of the battery.
No, you can use as much as you want. But Li-ion cells will age faster if you deplete them completely, so it's not the best way to keep your battery healthy.
< 40% is not "too far", it's just outside the optimal standing charge range for battery longevity, which studies have found is 40-80%.
In other words you can use your battery from 100% all the way down to shutdown- but the more time it spends in the 40-80% range, the longer its service life.
I've pulled out batteries out of working laptops to test just that theory - only a 2006 Toshiba P300 shut down, the rest of them (newer, Fujitsu, Dell and HP) ran uninterrupted. Either they switched faster or more likely, ran off the AC all the time. It's just good design...
I've often popped the batteries out of ThinkPad's when they are full and just ran on the wall wart. I don't know if they bypass automatically, but you can certainly just pop the battery out yourself.
It's correct that you'll retain battery capacity better if you store it at 40-80%. But that recommendation is based on long-term storage.
It's not right to assume that also applies to in-use products, especially the way people use them. In fact you'd likely reduce battery life because you're putting the battery through a greater depth of discharge (DoD). Assume you let it run from 80% to 60%, you've just gone through a cycle of 20% discharge when you could have kept the DoD at 1%. Also, most modern laptops will run on power once charged, so it's not like an infinite number of 1% cycles.
Have manufacturers never considered this? If leaving them at 80% was better, they would've configured the adapters to do just that. Unless they really wanted to sell extra batteries, of course...
As I sit and look at the replies already coming in, may I just add an enormous [citation needed] to the entire discussion? A question brought on by too many conflicting anecdotes can not be resolved by throwing another unsourced anecdote on the pile.
(Incidentally, I'm at least a bit curious myself as to the answer, and have my own pile of conflicting anecdotes I've read.)
Statistics and citations today is the Bible quotes / racial stereotypes of yesteryear. Some modern-day pseudo-scientist poster will cite some study that says "80% of chargers waste power if left plugged in at 100% charge" will then draw the logically faulty conclusion that therefore you should unplug your charger. The fact that the statistic study necessary had to ignore extra variables like if you have a lot of stuff plugged in, whether you're drawing power from a set of solar panels on your roof, whether you are using a super-special non-power wasting adapter, etc., necessarily makes the citation not a thought more credible than your great-great grandpa quoting the bible to tell you that you should marry your own race or citing stereotypes that you shouldn't trust your friend because he is Asian.
True science, that is, proposing hypothetical models, analyzing results, and admitting no real results can be drawn due to insufficient model complexity, has been thrown out the window by pride and laziness.
The question is simply "what do we know about this problem" not "what is the absolute unquestionable universal answer."
Also your comment has some interesting points but starting off by comparing statistics and citations to bible quotes and racial stereotypes isn't going to win you much support.
It's difficult to argue the idea that any manufacturer of a device containing a battery cell would not engineer the system for the proper balance of longevity, capacity, and durability to result in acceptable quality to customers.
If I were running a social network like this, I'd post questions with definitive answers like this one, see who voted up / wrote the wrong answers, and then block those people from voting / commenting again for a long time period.
Do that enough times, and you'd quickly have the smartest site on the Internet.
This thread literally has people posting links to Yahoo Answers.
Its best to consult with your laptop/charger/battery manual.
If anything goes wrong, new battery costs like $20. Feel sorry for battery prices for Macbook users, but then their charger is smart enough to help battery survive longer.
You could remove the battery when its charged and stay on the cord. Because battery life is heat-related. And leaving a charged battery in the laptop when you have a cord is chewing up lifetime without benefit.
And even when it appears to work, it may result in the processor being throttled so as not to overtax the power adapter without the battery available to supplement it.
Are there really laptops where you can't remove the battery when connected? I've never had one that wouldn't keep running when you pull the battery when on ac.
However the reason I know this is the same reason I keep mine in: I've dropped every laptop I've ever owned on the floor multiple times, and I've had one or the other of battery or charger cable fall out at least once for all of them, at least with the battery in the chances of losing power is reduced (though I have on occasion had both fall out at the same time).
Many laptops (such as all current Apple models) have built-in batteries. I guess you could remove the battery with special tools, but putting it back in may require re-gluing things.
> For proper maintenance of a lithium-based battery, it’s important to keep the electrons in it moving occasionally. Apple does not recommend leaving your portable plugged in all the time. An ideal use would be a commuter who uses her notebook on the train, then plugs it in at the office to charge. This keeps the battery juices flowing. If on the other hand, you use a desktop computer at work, and save a notebook for infrequent travel, Apple recommends charging and discharging its battery at least once per month.
Usually the reason behind discharging fully once per month is because when this happens, the laptop records how much capacity is required to recharge the battery. This will keep your battery % left accurate.
The actual preference for getting the MOST DISCHARGES out of a lithium ion battery is discharging it to 50%. This, however, doesn't not to equate to longest battery life (in terms of age) for the use within a laptop/phone.
Edit: There is something state of charge estimation models which may rely on this variable to decide how full they'll charge the battery. If you don't fully discharge and fully recharge the battery to update this capacity value, the SOC estimation model might overcharge the battery, thus decreasing the lifespan.
It specifically calls out recharging it to 50% every six months, so I assume it's a month+ kind of long term.
Also Apple seems to indicate that storage in a deep discharge state is far more damaging than storage at near-capacity based on the wording.
So if you're in doubt, charge it before you store it.
Finally, I don't think there's anything on that page that says you shouldn't keep your laptop plugged in when it's at 100%. I would be very surprised if they didn't have some cycle-conditioning going on. I have both a 2008 unibody and 2010 MBP, both essentially remaining plugged in for years. I don't think the battery life is abnormally low for their age, they still are capable of several hours of usage on battery.
Indeed. From my understanding, while this is still technically true, they have replaced the need for users to do anything with chips in the batteries themselves which shut off recharging when they're near 100%.
That's why if you pay attention you'll often see your battery % go from 97%-100% and then back down to 97%. It is reporting as "charging" but in reality it goes idle to let the battery de-charge a little.
Similar to a mechanical device that wears out faster with heavy use, so also does the depth of discharge (DoD) determine the cycle count. The shorter the discharge (low DoD), the longer the battery will last. If at all possible, avoid full discharges and charge the battery more often between uses. Partial discharge on Li-ion is fine. There is no memory and the battery does not need periodic full discharge cycles to prolong life.
To answer your question: No.
Side note: Don't blindly trust the manufacturer. Of course Apple wants you to wear out your laptop as fast as possible, once it's past the warranty. They're a business.
Side note 2: Laptops do NOT charge your battery to 100%. Your battery indicator is fake. 100% on your battery indicator is more like 90% in reality. The charger automatically cuts off before it reaches the true 100%, so all of the comments in this thread about 100% being bad are wrong, because no modern laptops will truly let you reach 100%.
My understanding (again, uncited, like almost everything in these threads) is that one might /perceive/ a different result than this because the /software/ calibrates what 0 and 100% mean based on observation.
If you never observe a zero (or, presumably, a 100%), it might recalibrate incorrectly. Again, this is based on old and uncited knowledge. There's surely someone here involved in writing power management software that could chime in.
Why would the battery be heated if it's not charging? You can set a gap - e.g. 80-100% where the battery won't start charging until it drops below 80%. Look at the documentation for your relevant power-management module.
Put the back of your hand (or your bare leg skin) against a laptop that's been in use. My Macbook is noticeably warm (maybe 15*F delta) in normal, non-charging, operation. That's with the benefit of conduction to the free air; I assume the inside delta-T is higher.
That's not answering my skepticism to GGP's post - what he is saying is: a non-charging plugged in device has a significantly hotter battery than a non-plugged in device because of thermal-conduction across a non-charging wire?
Not sure if it's exactly pertinent, but If I remember correctly tesla recommends draining your battery to 20% then charging back up to 80% when driving on a road trip, but this if mostly for speed of charging. The car battery charges fastest in this half-full range, charging past 80% to 100% is a exponential rate like blowing air into an already full balloon, it gets harder as you reach 100%.. to their recommendation is not necessarily about battery health but more likely about reducing the speed of your mid-trip recharge.
Lenovo at one time (they still might, I'm not sure) included a piece of software that allowed the user to optimize charging for battery life. Basically, it would stop the battery from reaching 100% of a charge.
Great idea, except that if you forgot to turn this feature off and had to leave, you might leave the house with just 60% battery life.
I'm using a Lenovo now and they still have it. Old Samsung also had something similar, Battery Life Extender, which won't stops charging at 80% even when plugged.
Leaving it plugged in has the same effect as removing the battery while it's plugged in (and putting the battery in identical thermal conditions). (Just think: if it were bad, engineering a workaround would be simple.) It's fine to have the battery sit at 100% for short periods of time. The damage you get around the 100% number is from charging/discharging to/from 100%, or leaving it unused for long periods of time.
I do. From the mains. Not so much to "save the battery", but to reduce power consumption. The charger is still consuming some power all the time it's on, regardless of battery level.
Yeah, that's a great starting spot for putting these crazy myths to bed.
A lot of a people seem confused about two concepts in the article: ideal storage and depth of discharge. These are two separate concerns. If you try to maintain the ideal storage charge while it's in-use (say 40%), you're going to end up wearing your battery by putting it through unnecessarily deep discharge cycles.
Unless you want to plug and unplug every few minutes, you should probably just leave it plugged in.
i used to have a macbook that i used as a desktop in clamshell mode. i left it plugged in all the time. i never took it anywhere.
when i called apple to replace the battery on warranty because it had started to bulge/swell dangerously and not hold charge, they had me open up the system information panel to see how many cycles it had been through, and it was hilariously low, like, 4. they refused to warranty it.
so at the very least, if you care at all about your warranty coverage, you should probably cycle it normally.
Personal experience with IPAD 1, 4 years using it every day with full discharges every day more than 1,000 charge cycles.
When new full battery lasted 9 hours after 4 years lasts 8 hours.
I hate to sound like an ass, but I think I need to say something anyway... Is this the kind of question we want at HN? It's been done to death elsewhere, and is easily answered with a quick search.
I know there can be a fine line between a good, thought-provoking question and a useless one, and, to me at least, this seems too far on the "useless question" side of things. It's about basic hardware maintenance, and I'm honestly surprised it's gotten 37 points in 22 minutes (so far).
I'm not saying it's a bad question, but I am asking if HN is the place to ask it. There are already lots and lots of answers to this question. Maybe try Reddit, or any of the various hardware forums.
People are free to down vote me (and they have) for my opinion -- even though I've been polite and (I think) thoughtful. Even still, my opinion stands: HN is the wrong forum for this kind of question. There are many, many questions that HN isn't the place for... How should I charge my car battery? What's the best electric blanket? Should I use 10 or 12 gauge wire wire for my house? Maybe it would be a good question if the OP had researched it a bit first, and posted "surprising facts about your laptop battery" or something. But just a question about laptop batteries?
Each one of these kinds of questions takes away from better quality, thoughtful or surprising content, which is what I like most about HN.
If the question were about car batteries or electric blankets, I'd agree with you. But it's not; this is about laptop and mobile batteries, which concerns a huge percentage of HN users. That's also why this thread is so active. I'm in the 8-year club here on HN and I don't have a problem with it.
I do leave small laptop on suspend overnight (not plugged in) and then I do use it on the train into work, so a small charge/discharge cycle each day.
The big typing box laptop (ancient T61p) is left on and plugged in a lot. May use a timer switch on the wall plug simply to reduce reliance on the overcharge protection in the battery/charger.
I think those with devices that have batteries that cannot be replaced may be more concerned.
Sure, but do you know what cells these batteries use? They're usually cheap chinese ones, of less than half the rated capacity. A proper replacement will cost much more.
I did go mid-way, buying high quality Japanese cells and installing them in a chinese pack. A bit cheaper than a new official battery, but required some work.
Assuming your computer has a replaceable battery, which is not the case always. Replacing a $80 battery is worth it to avoid stress, but replacing a $2000 ultrabook may not be.
I would think your ultrabook would be past its manufacturer's warranty anyway at that point anyway and would be a candidate for some sort of DIY battery replacement.
Even if it's not made to be user-replaceable, surely it can be replaced by someone with the right skills and tools for much less than the full replacement cost of the entire device.
I think an environmentalist just died a little bit after reading this.
But yes, this is the only sweeping statement that could be universally applied. Anything else is just anecdotal and something to talk about at the next happy hour.
This has happened to several dell and hp laptops I've owned or used long term, but both apple ones still keep charges for close to 3 hours even around 3 years after purchase without replacing the battery.
248 comments
[ 3.1 ms ] story [ 257 ms ] threadThe problem with leaving it at 100% is that just sitting at full charge wears it out, it's better to just keep it within 40%-80% than to leave it fully charged.
If you really want to, you can do a little bit of good by letting it drop to 40=80% during periods of non-use.
Too bad that some batteries wear out even faster this way because of the heat.
http://batteryuniversity.com/learn/article/how_to_prolong_li...
I don't know how much reserve they keep on hand, but what your OS reports as 0% charge is almost never actually that low.
In other words you can use your battery from 100% all the way down to shutdown- but the more time it spends in the 40-80% range, the longer its service life.
Letting the battery sit at 100% wears it out more than sitting at 40-80%.
It's not right to assume that also applies to in-use products, especially the way people use them. In fact you'd likely reduce battery life because you're putting the battery through a greater depth of discharge (DoD). Assume you let it run from 80% to 60%, you've just gone through a cycle of 20% discharge when you could have kept the DoD at 1%. Also, most modern laptops will run on power once charged, so it's not like an infinite number of 1% cycles.
http://batteryuniversity.com/learn/article/how_to_prolong_li...
(Incidentally, I'm at least a bit curious myself as to the answer, and have my own pile of conflicting anecdotes I've read.)
True science, that is, proposing hypothetical models, analyzing results, and admitting no real results can be drawn due to insufficient model complexity, has been thrown out the window by pride and laziness.
First, we need to start by assuming a sphererical laptop...
The question is simply "what do we know about this problem" not "what is the absolute unquestionable universal answer."
Also your comment has some interesting points but starting off by comparing statistics and citations to bible quotes and racial stereotypes isn't going to win you much support.
Do that enough times, and you'd quickly have the smartest site on the Internet.
This thread literally has people posting links to Yahoo Answers.
If anything goes wrong, new battery costs like $20. Feel sorry for battery prices for Macbook users, but then their charger is smart enough to help battery survive longer.
However the reason I know this is the same reason I keep mine in: I've dropped every laptop I've ever owned on the floor multiple times, and I've had one or the other of battery or charger cable fall out at least once for all of them, at least with the battery in the chances of losing power is reduced (though I have on occasion had both fall out at the same time).
Oh, if only that were true...
— https://web.archive.org/web/20110521104819/http://www.apple.... via http://apple.stackexchange.com/a/12280
This could also be useful, but doesn't answer the question directly: http://www.apple.com/batteries/maximizing-performance/
The actual preference for getting the MOST DISCHARGES out of a lithium ion battery is discharging it to 50%. This, however, doesn't not to equate to longest battery life (in terms of age) for the use within a laptop/phone.
Edit: There is something state of charge estimation models which may rely on this variable to decide how full they'll charge the battery. If you don't fully discharge and fully recharge the battery to update this capacity value, the SOC estimation model might overcharge the battery, thus decreasing the lifespan.
https://www.apple.com/batteries/maximizing-performance/
They don't say what "long-term" is, but monthly seems reasonable to me.
Also Apple seems to indicate that storage in a deep discharge state is far more damaging than storage at near-capacity based on the wording.
So if you're in doubt, charge it before you store it.
Finally, I don't think there's anything on that page that says you shouldn't keep your laptop plugged in when it's at 100%. I would be very surprised if they didn't have some cycle-conditioning going on. I have both a 2008 unibody and 2010 MBP, both essentially remaining plugged in for years. I don't think the battery life is abnormally low for their age, they still are capable of several hours of usage on battery.
That's why if you pay attention you'll often see your battery % go from 97%-100% and then back down to 97%. It is reporting as "charging" but in reality it goes idle to let the battery de-charge a little.
http://batteryuniversity.com/learn/article/how_to_prolong_li...
Summary:
Similar to a mechanical device that wears out faster with heavy use, so also does the depth of discharge (DoD) determine the cycle count. The shorter the discharge (low DoD), the longer the battery will last. If at all possible, avoid full discharges and charge the battery more often between uses. Partial discharge on Li-ion is fine. There is no memory and the battery does not need periodic full discharge cycles to prolong life.
To answer your question: No.
Side note: Don't blindly trust the manufacturer. Of course Apple wants you to wear out your laptop as fast as possible, once it's past the warranty. They're a business.
Side note 2: Laptops do NOT charge your battery to 100%. Your battery indicator is fake. 100% on your battery indicator is more like 90% in reality. The charger automatically cuts off before it reaches the true 100%, so all of the comments in this thread about 100% being bad are wrong, because no modern laptops will truly let you reach 100%.
If you never observe a zero (or, presumably, a 100%), it might recalibrate incorrectly. Again, this is based on old and uncited knowledge. There's surely someone here involved in writing power management software that could chime in.
https://answers.yahoo.com/question/index?qid=20130825212946A...
Lithium ion batteries do seem to have memory.
Heat transfer from the device it's plugged into.
Great idea, except that if you forgot to turn this feature off and had to leave, you might leave the house with just 60% battery life.
https://forums.lenovo.com/t5/image/serverpage/image-id/34801...
http://batteryuniversity.com/learn/article/how_to_prolong_li...
A lot of a people seem confused about two concepts in the article: ideal storage and depth of discharge. These are two separate concerns. If you try to maintain the ideal storage charge while it's in-use (say 40%), you're going to end up wearing your battery by putting it through unnecessarily deep discharge cycles.
Unless you want to plug and unplug every few minutes, you should probably just leave it plugged in.
when i called apple to replace the battery on warranty because it had started to bulge/swell dangerously and not hold charge, they had me open up the system information panel to see how many cycles it had been through, and it was hilariously low, like, 4. they refused to warranty it.
so at the very least, if you care at all about your warranty coverage, you should probably cycle it normally.
I know there can be a fine line between a good, thought-provoking question and a useless one, and, to me at least, this seems too far on the "useless question" side of things. It's about basic hardware maintenance, and I'm honestly surprised it's gotten 37 points in 22 minutes (so far).
People are free to down vote me (and they have) for my opinion -- even though I've been polite and (I think) thoughtful. Even still, my opinion stands: HN is the wrong forum for this kind of question. There are many, many questions that HN isn't the place for... How should I charge my car battery? What's the best electric blanket? Should I use 10 or 12 gauge wire wire for my house? Maybe it would be a good question if the OP had researched it a bit first, and posted "surprising facts about your laptop battery" or something. But just a question about laptop batteries?
Each one of these kinds of questions takes away from better quality, thoughtful or surprising content, which is what I like most about HN.
In short, leave it in because it's not worth worrying about.
I do leave small laptop on suspend overnight (not plugged in) and then I do use it on the train into work, so a small charge/discharge cycle each day.
The big typing box laptop (ancient T61p) is left on and plugged in a lot. May use a timer switch on the wall plug simply to reduce reliance on the overcharge protection in the battery/charger.
I think those with devices that have batteries that cannot be replaced may be more concerned.
I did go mid-way, buying high quality Japanese cells and installing them in a chinese pack. A bit cheaper than a new official battery, but required some work.
But yes, this is the only sweeping statement that could be universally applied. Anything else is just anecdotal and something to talk about at the next happy hour.
This has happened to several dell and hp laptops I've owned or used long term, but both apple ones still keep charges for close to 3 hours even around 3 years after purchase without replacing the battery.